Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
[linux-2.6] / drivers / isdn / i4l / isdn_v110.c
1 /* $Id: isdn_v110.c,v 1.1.2.2 2004/01/12 22:37:19 keil Exp $
2  *
3  * Linux ISDN subsystem, V.110 related functions (linklevel).
4  *
5  * Copyright by Thomas Pfeiffer (pfeiffer@pds.de)
6  *
7  * This software may be used and distributed according to the terms
8  * of the GNU General Public License, incorporated herein by reference.
9  *
10  */
11
12 #include <linux/string.h>
13 #include <linux/kernel.h>
14 #include <linux/slab.h>
15 #include <linux/mm.h>
16 #include <linux/delay.h>
17
18 #include <linux/isdn.h>
19 #include "isdn_v110.h"
20
21 #undef ISDN_V110_DEBUG
22
23 char *isdn_v110_revision = "$Revision: 1.1.2.2 $";
24
25 #define V110_38400 255
26 #define V110_19200  15
27 #define V110_9600    3
28
29 /* 
30  * The following data are precoded matrices, online and offline matrix 
31  * for 9600, 19200 und 38400, respectively
32  */
33 static unsigned char V110_OnMatrix_9600[] =
34 {0xfc, 0xfc, 0xfc, 0xfc, 0xff, 0xff, 0xff, 0xfd, 0xff, 0xff,
35  0xff, 0xfd, 0xff, 0xff, 0xff, 0xfd, 0xff, 0xff, 0xff, 0xfd,
36  0xfd, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfd, 0xff, 0xff,
37  0xff, 0xfd, 0xff, 0xff, 0xff, 0xfd, 0xff, 0xff, 0xff, 0xfd};
38
39 static unsigned char V110_OffMatrix_9600[] =
40 {0xfc, 0xfc, 0xfc, 0xfc, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
41  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
42  0xfd, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
43  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
44
45 static unsigned char V110_OnMatrix_19200[] =
46 {0xf0, 0xf0, 0xff, 0xf7, 0xff, 0xf7, 0xff, 0xf7, 0xff, 0xf7,
47  0xfd, 0xff, 0xff, 0xf7, 0xff, 0xf7, 0xff, 0xf7, 0xff, 0xf7};
48
49 static unsigned char V110_OffMatrix_19200[] =
50 {0xf0, 0xf0, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
51  0xfd, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
52
53 static unsigned char V110_OnMatrix_38400[] =
54 {0x00, 0x7f, 0x7f, 0x7f, 0x7f, 0xfd, 0x7f, 0x7f, 0x7f, 0x7f};
55
56 static unsigned char V110_OffMatrix_38400[] =
57 {0x00, 0xff, 0xff, 0xff, 0xff, 0xfd, 0xff, 0xff, 0xff, 0xff};
58
59 /* 
60  * FlipBits reorders sequences of keylen bits in one byte.
61  * E.g. source order 7654321 will be converted to 45670123 when keylen = 4,
62  * and to 67452301 when keylen = 2. This is necessary because ordering on
63  * the isdn line is the other way.
64  */
65 static __inline unsigned char
66 FlipBits(unsigned char c, int keylen)
67 {
68         unsigned char b = c;
69         unsigned char bit = 128;
70         int i;
71         int j;
72         int hunks = (8 / keylen);
73
74         c = 0;
75         for (i = 0; i < hunks; i++) {
76                 for (j = 0; j < keylen; j++) {
77                         if (b & (bit >> j))
78                                 c |= bit >> (keylen - j - 1);
79                 }
80                 bit >>= keylen;
81         }
82         return c;
83 }
84
85
86 /* isdn_v110_open allocates and initializes private V.110 data
87  * structures and returns a pointer to these.
88  */
89 static isdn_v110_stream *
90 isdn_v110_open(unsigned char key, int hdrlen, int maxsize)
91 {
92         int i;
93         isdn_v110_stream *v;
94
95         if ((v = kzalloc(sizeof(isdn_v110_stream), GFP_ATOMIC)) == NULL)
96                 return NULL;
97         v->key = key;
98         v->nbits = 0;
99         for (i = 0; key & (1 << i); i++)
100                 v->nbits++;
101
102         v->nbytes = 8 / v->nbits;
103         v->decodelen = 0;
104
105         switch (key) {
106                 case V110_38400:
107                         v->OnlineFrame = V110_OnMatrix_38400;
108                         v->OfflineFrame = V110_OffMatrix_38400;
109                         break;
110                 case V110_19200:
111                         v->OnlineFrame = V110_OnMatrix_19200;
112                         v->OfflineFrame = V110_OffMatrix_19200;
113                         break;
114                 default:
115                         v->OnlineFrame = V110_OnMatrix_9600;
116                         v->OfflineFrame = V110_OffMatrix_9600;
117                         break;
118         }
119         v->framelen = v->nbytes * 10;
120         v->SyncInit = 5;
121         v->introducer = 0;
122         v->dbit = 1;
123         v->b = 0;
124         v->skbres = hdrlen;
125         v->maxsize = maxsize - hdrlen;
126         if ((v->encodebuf = kmalloc(maxsize, GFP_ATOMIC)) == NULL) {
127                 kfree(v);
128                 return NULL;
129         }
130         return v;
131 }
132
133 /* isdn_v110_close frees private V.110 data structures */
134 void
135 isdn_v110_close(isdn_v110_stream * v)
136 {
137         if (v == NULL)
138                 return;
139 #ifdef ISDN_V110_DEBUG
140         printk(KERN_DEBUG "v110 close\n");
141 #endif
142         kfree(v->encodebuf);
143         kfree(v);
144 }
145
146
147 /* 
148  * ValidHeaderBytes return the number of valid bytes in v->decodebuf 
149  */
150 static int
151 ValidHeaderBytes(isdn_v110_stream * v)
152 {
153         int i;
154         for (i = 0; (i < v->decodelen) && (i < v->nbytes); i++)
155                 if ((v->decodebuf[i] & v->key) != 0)
156                         break;
157         return i;
158 }
159
160 /* 
161  * SyncHeader moves the decodebuf ptr to the next valid header 
162  */
163 static void
164 SyncHeader(isdn_v110_stream * v)
165 {
166         unsigned char *rbuf = v->decodebuf;
167         int len = v->decodelen;
168
169         if (len == 0)
170                 return;
171         for (rbuf++, len--; len > 0; len--, rbuf++)     /* such den SyncHeader in buf ! */
172                 if ((*rbuf & v->key) == 0)      /* erstes byte gefunden ?       */
173                         break;  /* jupp!                        */
174         if (len)
175                 memcpy(v->decodebuf, rbuf, len);
176
177         v->decodelen = len;
178 #ifdef ISDN_V110_DEBUG
179         printk(KERN_DEBUG "isdn_v110: Header resync\n");
180 #endif
181 }
182
183 /* DecodeMatrix takes n (n>=1) matrices (v110 frames, 10 bytes) where
184    len is the number of matrix-lines. len must be a multiple of 10, i.e.
185    only complete matices must be given.
186    From these, netto data is extracted and returned in buf. The return-value
187    is the bytecount of the decoded data.
188  */
189 static int
190 DecodeMatrix(isdn_v110_stream * v, unsigned char *m, int len, unsigned char *buf)
191 {
192         int line = 0;
193         int buflen = 0;
194         int mbit = 64;
195         int introducer = v->introducer;
196         int dbit = v->dbit;
197         unsigned char b = v->b;
198
199         while (line < len) {    /* Are we done with all lines of the matrix? */
200                 if ((line % 10) == 0) { /* the 0. line of the matrix is always 0 ! */
201                         if (m[line] != 0x00) {  /* not 0 ? -> error! */
202 #ifdef ISDN_V110_DEBUG
203                                 printk(KERN_DEBUG "isdn_v110: DecodeMatrix, V110 Bad Header\n");
204                                 /* returning now is not the right thing, though :-( */
205 #endif
206                         } 
207                         line++; /* next line of matrix */
208                         continue;
209                 } else if ((line % 10) == 5) {  /* in line 5 there's only e-bits ! */
210                         if ((m[line] & 0x70) != 0x30) { /* 011 has to be at the beginning! */
211 #ifdef ISDN_V110_DEBUG
212                                 printk(KERN_DEBUG "isdn_v110: DecodeMatrix, V110 Bad 5th line\n");
213                                 /* returning now is not the right thing, though :-( */
214 #endif
215                         }
216                         line++; /* next line */
217                         continue;
218                 } else if (!introducer) {       /* every byte starts with 10 (stopbit, startbit) */
219                         introducer = (m[line] & mbit) ? 0 : 1;  /* current bit of the matrix */
220                       next_byte:
221                         if (mbit > 2) { /* was it the last bit in this line ? */
222                                 mbit >>= 1;     /* no -> take next */
223                                 continue;
224                         }       /* otherwise start with leftmost bit in the next line */
225                         mbit = 64;
226                         line++;
227                         continue;
228                 } else {        /* otherwise we need to set a data bit */
229                         if (m[line] & mbit)     /* was that bit set in the matrix ? */
230                                 b |= dbit;      /* yes -> set it in the data byte */
231                         else
232                                 b &= dbit - 1;  /* no -> clear it in the data byte */
233                         if (dbit < 128) /* is that data byte done ? */
234                                 dbit <<= 1;     /* no, got the next bit */
235                         else {  /* data byte is done */
236                                 buf[buflen++] = b;      /* copy byte into the output buffer */
237                                 introducer = b = 0;     /* init of the intro sequence and of the data byte */
238                                 dbit = 1;       /* next we look for the 0th bit */
239                         }
240                         goto next_byte; /* look for next bit in the matrix */
241                 }
242         }
243         v->introducer = introducer;
244         v->dbit = dbit;
245         v->b = b;
246         return buflen;          /* return number of bytes in the output buffer */
247 }
248
249 /* 
250  * DecodeStream receives V.110 coded data from the input stream. It recovers the 
251  * original frames.
252  * The input stream doesn't need to be framed
253  */
254 struct sk_buff *
255 isdn_v110_decode(isdn_v110_stream * v, struct sk_buff *skb)
256 {
257         int i;
258         int j;
259         int len;
260         unsigned char *v110_buf;
261         unsigned char *rbuf;
262
263         if (!skb) {
264                 printk(KERN_WARNING "isdn_v110_decode called with NULL skb!\n");
265                 return NULL;
266         }
267         rbuf = skb->data;
268         len = skb->len;
269         if (v == NULL) {
270                 /* invalid handle, no chance to proceed */
271                 printk(KERN_WARNING "isdn_v110_decode called with NULL stream!\n");
272                 dev_kfree_skb(skb);
273                 return NULL;
274         }
275         if (v->decodelen == 0)  /* cache empty?               */
276                 for (; len > 0; len--, rbuf++)  /* scan for SyncHeader in buf */
277                         if ((*rbuf & v->key) == 0)
278                                 break;  /* found first byte           */
279         if (len == 0) {
280                 dev_kfree_skb(skb);
281                 return NULL;
282         }
283         /* copy new data to decode-buffer */
284         memcpy(&(v->decodebuf[v->decodelen]), rbuf, len);
285         v->decodelen += len;
286       ReSync:
287         if (v->decodelen < v->nbytes) { /* got a new header ? */
288                 dev_kfree_skb(skb);
289                 return NULL;    /* no, try later      */
290         }
291         if (ValidHeaderBytes(v) != v->nbytes) { /* is that a valid header? */
292                 SyncHeader(v);  /* no -> look for header */
293                 goto ReSync;
294         }
295         len = (v->decodelen - (v->decodelen % (10 * v->nbytes))) / v->nbytes;
296         if ((v110_buf = kmalloc(len, GFP_ATOMIC)) == NULL) {
297                 printk(KERN_WARNING "isdn_v110_decode: Couldn't allocate v110_buf\n");
298                 dev_kfree_skb(skb);
299                 return NULL;
300         }
301         for (i = 0; i < len; i++) {
302                 v110_buf[i] = 0;
303                 for (j = 0; j < v->nbytes; j++)
304                         v110_buf[i] |= (v->decodebuf[(i * v->nbytes) + j] & v->key) << (8 - ((j + 1) * v->nbits));
305                 v110_buf[i] = FlipBits(v110_buf[i], v->nbits);
306         }
307         v->decodelen = (v->decodelen % (10 * v->nbytes));
308         memcpy(v->decodebuf, &(v->decodebuf[len * v->nbytes]), v->decodelen);
309
310         skb_trim(skb, DecodeMatrix(v, v110_buf, len, skb->data));
311         kfree(v110_buf);
312         if (skb->len)
313                 return skb;
314         else {
315                 kfree_skb(skb);
316                 return NULL;
317         }
318 }
319
320 /* EncodeMatrix takes input data in buf, len is the bytecount.
321    Data is encoded into v110 frames in m. Return value is the number of
322    matrix-lines generated.
323  */
324 static int
325 EncodeMatrix(unsigned char *buf, int len, unsigned char *m, int mlen)
326 {
327         int line = 0;
328         int i = 0;
329         int mbit = 128;
330         int dbit = 1;
331         int introducer = 3;
332         int ibit[] = {0, 1, 1};
333
334         while ((i < len) && (line < mlen)) {    /* while we still have input data */
335                 switch (line % 10) {    /* in which line of the matrix are we? */
336                         case 0:
337                                 m[line++] = 0x00;       /* line 0 is always 0 */
338                                 mbit = 128;     /* go on with the 7th bit */
339                                 break;
340                         case 5:
341                                 m[line++] = 0xbf;       /* line 5 is always 10111111 */
342                                 mbit = 128;     /* go on with the 7th bit */
343                                 break;
344                 }
345                 if (line >= mlen) {
346                         printk(KERN_WARNING "isdn_v110 (EncodeMatrix): buffer full!\n");
347                         return line;
348                 }
349         next_bit:
350                 switch (mbit) { /* leftmost or rightmost bit ? */
351                         case 1:
352                                 line++; /* rightmost -> go to next line */
353                                 if (line >= mlen) {
354                                         printk(KERN_WARNING "isdn_v110 (EncodeMatrix): buffer full!\n");
355                                         return line;
356                                 }
357                         case 128:
358                                 m[line] = 128;  /* leftmost -> set byte to 1000000 */
359                                 mbit = 64;      /* current bit in the matrix line */
360                                 continue;
361                 }
362                 if (introducer) {       /* set 110 sequence ? */
363                         introducer--;   /* set on digit less */
364                         m[line] |= ibit[introducer] ? mbit : 0; /* set corresponding bit */
365                         mbit >>= 1;     /* bit of matrix line  >> 1 */
366                         goto next_bit;  /* and go on there */
367                 }               /* else push data bits into the matrix! */
368                 m[line] |= (buf[i] & dbit) ? mbit : 0;  /* set data bit in matrix */
369                 if (dbit == 128) {      /* was it the last one? */
370                         dbit = 1;       /* then go on with first bit of  */
371                         i++;            /* next byte in input buffer */
372                         if (i < len)    /* input buffer done ? */
373                                 introducer = 3; /* no, write introducer 110 */
374                         else {  /* input buffer done ! */
375                                 m[line] |= (mbit - 1) & 0xfe;   /* set remaining bits in line to 1 */
376                                 break;
377                         }
378                 } else          /* not the last data bit */
379                         dbit <<= 1;     /* then go to next data bit */
380                 mbit >>= 1;     /* go to next bit of matrix */
381                 goto next_bit;
382
383         }
384         /* if necessary, generate remaining lines of the matrix... */
385         if ((line) && ((line + 10) < mlen))
386                 switch (++line % 10) {
387                         case 1:
388                                 m[line++] = 0xfe;
389                         case 2:
390                                 m[line++] = 0xfe;
391                         case 3:
392                                 m[line++] = 0xfe;
393                         case 4:
394                                 m[line++] = 0xfe;
395                         case 5:
396                                 m[line++] = 0xbf;
397                         case 6:
398                                 m[line++] = 0xfe;
399                         case 7:
400                                 m[line++] = 0xfe;
401                         case 8:
402                                 m[line++] = 0xfe;
403                         case 9:
404                                 m[line++] = 0xfe;
405                 }
406         return line;            /* that's how many lines we have */
407 }
408
409 /*
410  * Build a sync frame.
411  */
412 static struct sk_buff *
413 isdn_v110_sync(isdn_v110_stream *v)
414 {
415         struct sk_buff *skb;
416
417         if (v == NULL) {
418                 /* invalid handle, no chance to proceed */
419                 printk(KERN_WARNING "isdn_v110_sync called with NULL stream!\n");
420                 return NULL;
421         }
422         if ((skb = dev_alloc_skb(v->framelen + v->skbres))) {
423                 skb_reserve(skb, v->skbres);
424                 memcpy(skb_put(skb, v->framelen), v->OfflineFrame, v->framelen);
425         }
426         return skb;
427 }
428
429 /*
430  * Build an idle frame.
431  */
432 static struct sk_buff *
433 isdn_v110_idle(isdn_v110_stream *v)
434 {
435         struct sk_buff *skb;
436
437         if (v == NULL) {
438                 /* invalid handle, no chance to proceed */
439                 printk(KERN_WARNING "isdn_v110_sync called with NULL stream!\n");
440                 return NULL;
441         }
442         if ((skb = dev_alloc_skb(v->framelen + v->skbres))) {
443                 skb_reserve(skb, v->skbres);
444                 memcpy(skb_put(skb, v->framelen), v->OnlineFrame, v->framelen);
445         }
446         return skb;
447 }
448
449 struct sk_buff *
450 isdn_v110_encode(isdn_v110_stream * v, struct sk_buff *skb)
451 {
452         int i;
453         int j;
454         int rlen;
455         int mlen;
456         int olen;
457         int size;
458         int sval1;
459         int sval2;
460         int nframes;
461         unsigned char *v110buf;
462         unsigned char *rbuf;
463         struct sk_buff *nskb;
464
465         if (v == NULL) {
466                 /* invalid handle, no chance to proceed */
467                 printk(KERN_WARNING "isdn_v110_encode called with NULL stream!\n");
468                 return NULL;
469         }
470         if (!skb) {
471                 /* invalid skb, no chance to proceed */
472                 printk(KERN_WARNING "isdn_v110_encode called with NULL skb!\n");
473                 return NULL;
474         }
475         rlen = skb->len;
476         nframes = (rlen + 3) / 4;
477         v110buf = v->encodebuf;
478         if ((nframes * 40) > v->maxsize) {
479                 size = v->maxsize;
480                 rlen = v->maxsize / 40;
481         } else
482                 size = nframes * 40;
483         if (!(nskb = dev_alloc_skb(size + v->skbres + sizeof(int)))) {
484                 printk(KERN_WARNING "isdn_v110_encode: Couldn't alloc skb\n");
485                 return NULL;
486         }
487         skb_reserve(nskb, v->skbres + sizeof(int));
488         if (skb->len == 0) {
489                 memcpy(skb_put(nskb, v->framelen), v->OnlineFrame, v->framelen);
490                 *((int *)skb_push(nskb, sizeof(int))) = 0;
491                 return nskb;
492         }
493         mlen = EncodeMatrix(skb->data, rlen, v110buf, size);
494         /* now distribute 2 or 4 bits each to the output stream! */
495         rbuf = skb_put(nskb, size);
496         olen = 0;
497         sval1 = 8 - v->nbits;
498         sval2 = v->key << sval1;
499         for (i = 0; i < mlen; i++) {
500                 v110buf[i] = FlipBits(v110buf[i], v->nbits);
501                 for (j = 0; j < v->nbytes; j++) {
502                         if (size--)
503                                 *rbuf++ = ~v->key | (((v110buf[i] << (j * v->nbits)) & sval2) >> sval1);
504                         else {
505                                 printk(KERN_WARNING "isdn_v110_encode: buffers full!\n");
506                                 goto buffer_full;
507                         }
508                         olen++;
509                 }
510         }
511 buffer_full:
512         skb_trim(nskb, olen);
513         *((int *)skb_push(nskb, sizeof(int))) = rlen;
514         return nskb;
515 }
516
517 int
518 isdn_v110_stat_callback(int idx, isdn_ctrl *c)
519 {
520         isdn_v110_stream *v = NULL;
521         int i;
522         int ret = 0;
523
524         if (idx < 0)
525                 return 0;
526         switch (c->command) {
527                 case ISDN_STAT_BSENT:
528                         /* Keep the send-queue of the driver filled
529                          * with frames:
530                          * If number of outstanding frames < 3,
531                          * send down an Idle-Frame (or an Sync-Frame, if
532                          * v->SyncInit != 0). 
533                          */
534                         if (!(v = dev->v110[idx]))
535                                 return 0;
536                         atomic_inc(&dev->v110use[idx]);
537                         for (i=0; i * v->framelen < c->parm.length; i++) {
538                                 if (v->skbidle > 0) {
539                                         v->skbidle--;
540                                         ret = 1;
541                                 } else {
542                                         if (v->skbuser > 0)
543                                                 v->skbuser--;
544                                         ret = 0;
545                                 }
546                         }
547                         for (i = v->skbuser + v->skbidle; i < 2; i++) {
548                                 struct sk_buff *skb;
549                                 if (v->SyncInit > 0)
550                                         skb = isdn_v110_sync(v);
551                                 else
552                                         skb = isdn_v110_idle(v);
553                                 if (skb) {
554                                         if (dev->drv[c->driver]->interface->writebuf_skb(c->driver, c->arg, 1, skb) <= 0) {
555                                                 dev_kfree_skb(skb);
556                                                 break;
557                                         } else {
558                                                 if (v->SyncInit)
559                                                         v->SyncInit--;
560                                                 v->skbidle++;
561                                         }
562                                 } else
563                                         break;
564                         }
565                         atomic_dec(&dev->v110use[idx]);
566                         return ret;
567                 case ISDN_STAT_DHUP:
568                 case ISDN_STAT_BHUP:
569                         while (1) {
570                                 atomic_inc(&dev->v110use[idx]);
571                                 if (atomic_dec_and_test(&dev->v110use[idx])) {
572                                         isdn_v110_close(dev->v110[idx]);
573                                         dev->v110[idx] = NULL;
574                                         break;
575                                 }
576                                 mdelay(1);
577                         }
578                         break;
579                 case ISDN_STAT_BCONN:
580                         if (dev->v110emu[idx] && (dev->v110[idx] == NULL)) {
581                                 int hdrlen = dev->drv[c->driver]->interface->hl_hdrlen;
582                                 int maxsize = dev->drv[c->driver]->interface->maxbufsize;
583                                 atomic_inc(&dev->v110use[idx]);
584                                 switch (dev->v110emu[idx]) {
585                                         case ISDN_PROTO_L2_V11096:
586                                                 dev->v110[idx] = isdn_v110_open(V110_9600, hdrlen, maxsize);
587                                                 break;
588                                         case ISDN_PROTO_L2_V11019:
589                                                 dev->v110[idx] = isdn_v110_open(V110_19200, hdrlen, maxsize);
590                                                 break;
591                                         case ISDN_PROTO_L2_V11038:
592                                                 dev->v110[idx] = isdn_v110_open(V110_38400, hdrlen, maxsize);
593                                                 break;
594                                         default:;
595                                 }
596                                 if ((v = dev->v110[idx])) {
597                                         while (v->SyncInit) {
598                                                 struct sk_buff *skb = isdn_v110_sync(v);
599                                                 if (dev->drv[c->driver]->interface->writebuf_skb(c->driver, c->arg, 1, skb) <= 0) {
600                                                         dev_kfree_skb(skb);
601                                                         /* Unable to send, try later */
602                                                         break;
603                                                 }
604                                                 v->SyncInit--;
605                                                 v->skbidle++;
606                                         }
607                                 } else
608                                         printk(KERN_WARNING "isdn_v110: Couldn't open stream for chan %d\n", idx);
609                                 atomic_dec(&dev->v110use[idx]);
610                         }
611                         break;
612                 default:
613                         return 0;
614         }
615         return 0;
616 }